Hydraulic draw press



June 17, '1941.' T RM ET-AL 2,246,021

HYDRAULIC DRAW PRESS F'i1 ed Dec. 16, 1938 5 Sheets-Sheet 1 Fig. 2.

' Fig.4.

' Fig.5.

June 17, 1941. J. sTuRM ETAL HYDRAULIC DRAW PRESS 16, 1938 3 Sheets-Sheet 2 Filed D ec.

M M W r K r A W T A: \a J V .74 N 1/ m u www w K %?7 2 MA mm 7 A 2 June 17, 194-1. J, STURM ETAL 2,246,021

HYDRAULIC DRAW PRESS Filed Dec. 16, 1938 3 Sheets-Sheet 3 Fig. 10.

Patented June 17, 1941 U iTED T I QFFICE HYDRAULIC DRAW PRESS Jakob Sturm and Adolf Hinderer, Goppingen, Germany, assignors to L. Schulcr, A. G Goppingen, Wurttcmburg, Germany Application December 16, 1938, Serial No. 246,180 In Germany December 23, 1937 11 Claims.

The present invention relates to hydraulic drawing presses, more particularly for sheet material of any kind, that is to say, having one or more slides and having either anupward or downward working stroke of the-slideor slidesu With these presses accidents happen owing to the fact that a slide, either due to wrong operation, leakage of packings or valves, or any other 7 slidably or swingably mounted in the frame of 2o the press. Either one slide only or several slides and, if necessary, all the slides of the press may be provided with this safety device. Other features of the invention will be fully explained with the aid of the drawings and are fully'set out in the claims. 1 1 a The accompanying drawings illustrate by way of example several embodiments of the invention. Fig. 1 shows an arrangement embodying the invention and having a. slidable locking bolt and ".30

shows diagrammatically the locking bolt and the control parts required for elucidating the invention.

Figs. 2 to 4 show the rod-lock mechanism of the linkage in various operative positions with respect to the initial position thereof.

Figs. 5 to '7 are similar views to Figs. 2 to 4 of a modified construction ofthe rod-lock.

Fig. 8 shows an arrangement in which swingahle locking dogs or pawls are used. Fig. 9 shows a further modified arrangement. Fig. 10 shows an additional operating device for a locking bolt.

Fig. 11 is a section on the line.XIXI of Fig. 10. V Fig. 12 shows the arrangement of a hand lever operating a locking bolt in an electricallycontrolled press.

Fig. 13 is a side view corresponding to Fig. 12.

The initial position of the hand lever for con- K trolling the press slide, that is to say that position in which the press is stationary, is indicated by numeral I. If the press is to be set in operation the hand lever is swung into the socalled advance run position indicated by II. .The ad- Vance run of the press slide is efiected at low pressure and causes the guiding of the slide directly up to the workpiece. The advance run is efiected relatively quickly. On the other hand the slide during the actual forming of the work- 5 again at high pressure.

piece is only moved slowly but at high pressure. For the purposeof efiecting this manner o f.operation of the press slide the hand lever ismoved into the so-called working position which is indicated by the numeral III. When the treatment of the workpiece has been completed thesocalled reverse run of the press is carried out For this purpose the hand lever is moved into the reverse run position indicated by IV. When the slide has again taken up the position'of rest the hand lever is finally moved back into the initial position I.

In Figs. 1 to 8, it is assumed that the reverse stroke of the slide is effected by returning the hand lever from the advance position through the initial position, whilst in Fig. 9 it is assumed that the reverse stroke of the slide is produced by moving the hand lever further in the same direction beyond the advance position. I

In the constructional example according .to Fig. l which shows only the right-hand portion of press frame 5, 2 indicates the adjacent portion of a press slide. The press slide is adapted to be supported by a slidably mounteddog in the form of bolt 3 having a nose portion '4 sufiiciently strong to support not only the weight of the slide 2 but also, if necessary, the low pressure acting thereon. Asa rule,.the high pressure does not act upon the slide in the initial position of the slide shown in Fig. 1, but only after the slide has performed its advance run. If necessary, however, the nose 4 may be designed sufliciently strong to enable the, bolt to stopthe movement of the slide 2 even when loaded by high pressure. In the position shown in Fig. 1, the bolt 3 is held in the locking position by a compression spring 6 held between the bolt and a fixed bush 5, the inward or projecting movement of the bolt by the said spring being limited by a collar formed on the said dog or bolt and bearing on a shoulder 76. The rear end of thebolt 3 engages a forked end .1 of an elbow lever 9 pivotally mounted at 8 in the press frame I. To the other end of the elbow lever.9 is pivotally connected a {rod Hi, the other end of which is connected with a further rod 12 by a sleeve H.

' the slide 2.

In the construction shown in Figs. 2 to 4. the rod lock is constructed as follows: The rod I has a slot IT in which slides a bolt 18 passed through the sleeve ll. Another'transverse bolt IB is passed through the end of the the p ositions II and I collar I5 bearing on the shoulder I6.

rod I2 and slides in two slots 20, 2| of the sleeve II.

The lock construction according to Figs. 5 to '7 is designed to meet the same requirement as that of Figs. 2 to 4. The plays between the rods I0, I2 and the sleeve II are, however, differently arranged. The rod In is fixedly connected by the transverse bolt IS with the sleeve I I, whilst the bolt I9, fixed in the rod I2, slides in longitudinal slots 20' and 2| of the sleeve II, the slots, however, being twice as long as the corresponding slots 20 and 2I of the sleeve II.

In the rest position of the press, the lock is in the position shown in Fig. 2 or 5 respectively. On moving the hand lever I6 into the position II corresponding to the advance run of the slide, the bolt 3 is moved, by means of the connecting rod I5, the elbow lever It, the parts I2, II, I and the elbow lever 9, so far to the right that the slide 2 may alvance freely, this movement being, in the construction shown in Fig. 1, in the downward direction. The positive downward movement of the rod I2 is, in this case, transmitted by the bolt I9 to the sleeve II and by the latter through the bolt I8 to the rod I0. To the position II of the hand lever I correspond the-positions of the parts III, I I, I2, shown in Figs. 2 and 5 respectively. On further moving the hand lever I6 to the working position proper.

III of the slide, which, for instance, may correspond to the clamping of the blank by the blank holder slide or to the shaping of the blank by the drawing slide, further downward movement of the parts I0, II, I2 takes place. So far the said parts III, II and I2 are still in the positions shown in Figs. 2 and 5 respectively, and the dog 3 is in retracted position. For reversing the slide, the hand lever I6 is moved back through into the position IV. During this movement, the rod I2 or IE is lifted higher than the position according to Fig. 1, see Fig. 3 or 6. This movement of the rod I2 or I2 beyond the position shown'in Figs. 1 and 2 or Fig. 5, however, should not affect the rod I0, elbow lever 9 and bolt 3 because the projecting movement of the said bolt is arrested by the This is attained by the provision of the slots 20, 2I or 28', 2I of the sleeve I I or II, in which the bolts I9 or I9 can slide. Provision must be made also to enable the slide 2, during its reverse stroke, to pass the bolt 3 and move into its initial position. This is attained, in the construction of the lock shown in Figs. 2 to 4 by the provision of the slot I? in the rod III, and a beveled cam face 11 provided at the projecting end of the dog '3 and adapted to be engaged by the slide 2. By this means, the bolt 3 can be, in opposition to the action of the spring 6, forced back by the slide 2 moving upwardly, and, at the same time, the rod ID may be lowered without influencing the position of the rod I2 and the hand lever I6. In the construction of the lock shown in Figs. 5 to 7, the temporary forcing back of the bolt 3 is permitted by the length of the slots 20', H, which are made so long as to allow the rod I2 and the hand lever It to remain unaffected. Thus it is clear that the bolt 3 is yieldingly held by the spring 6 in its operative position and that the rod system IE], II, I2 is so subdivided that the slide 2 can, during its reverse stroke, force the bolt 3, against the action of the force acting thereon, temporarily from its locking position without, at the same and 25.

there are mounted in the frame I of the p'fess a" blank holding slide 22 and a drawing slide or punch 23. The dog 24, which supports the blank holder slide 22, as in the form of a pawl, and is preferably provided with additional notches 25 In a similar manner, the dog or looking pawl 21, holding the drawing slide 23, is formed with several notches. The locking dogs or pawls 24 and 21 are swingably mounted in a head 28 of the press frame I, and are held in their locking positions by springs 29 and 30 respectively. Of the two hand levers I6, arranged preferably one behind the other, which serve for controlling the blank holder slide 22 and the drawing slide 23, only the lever corresponding to the blank holder slide 22 is shown. The transmission of the movement of the lever IE to the dog 24 takes place through a rod I5, an elbow lever I4, a rod I2, a sleeve II, a rod II and an elbow lever 9, the other arm of which forms the dog or pawl 24. The hand lever Iii, serving for controlling the drawing slide 23, is connected with the dog 21 in a similar manner by means of another elbow lever 3| and link 32. The mode of operation of this arrangement corresponds to that shown in Fig. 1 and in this construction too the rod system II), II, I2 may be constructed either as shown in Figs. 2 to 4 or as shown in Figs. 5 to '7.

Whilst, in connection with the constructional examples according to Figs. 1 to 8, it was assumed that the reverse 'stroke of the slide is effected by turning the hand lever I6 back from the position III through the initial position I into the reverse position, the construction shown in Fig. 9 shows an arrangement in which the reverse position of the slide is located behind the advance position so thatthe hand lever is, during a full cycle of operations, moved continuously in the same direction. In this construction, the connection between the hand lever I5 and the bolt 3 must be so designed that, in spite of continued movement of the hand lever I6 taking place in the same direction, the bolt 3 can move into its operative position before the reverse run of the slide 2. This is attained by the interposition in the operating mechanism of a toggle lever 33, 34 between the rods I2 and I5. The bolt 3 is, only in the position II of the hand lever I6, withdrawn to such an extent as to enable the slide 2 to advance freely. In the position IV, the bolt 3 is again in its locking position. The temporary putting out of action of the bolt 3 by the slide 2 during the reverse stroke is again attained by a construction of the parts III, II, I2 corresponding to that shown either in Figs. 2 to 4 or Figs. 5 to '7.

In the constructional examples according to Figs. 1 to 9, it is assumed that the same lever movement, which starts the advance of the slide. produces also the withdrawal of the safety bolt or bolts from their operative position. In other words, the control lever of the press is utilised for simultaneously operating the safety bolt or bolts. In the constructional examples according to Figs. 10, 11, 12 and 13, separate levers are provided for permitting advance of the slide by withdrawing the safety bolt or bolts from their operative position. In that case, it is advisable, however, to arrange the hand lever for controlling the advance run of the slide in such a manher with regard to the separate safety bolt lever or' levers, that the advance control lever can be actuated only after the lever operating the safety bolt or bolts has been actuated and, consequently,

the safety bolt has been withdrawn from its opin a double bearing bracket 58 upon a pivot 59.

The hand lever 60 for operating the safety bolt is connected with the safety bolt 3 by asuitable operating mechanism, whilst the lever 6| is used for controlling the operation of the slide. The hand lever $53 is drawn, by a spring 62, against a stop 63 so that, on being released byhand, it automatically returns to itsposition of rest. The hand lever 6i, controlling the operation of the slide, is provided with a cylindrical extension 64 in which a locking bolt 65, loaded by a spring 65, is slidably mounted. In the rest position, the bolt 66 projects from the cylinder 64 and abuts against the stationary stop 61. In order to start the working stroke of the slide, it is necessary to move the hand lever 6| in the clockwise direction downwards. This movement, how. ever, cannot be effected whilst thebolt 66 projects from the cylinder 64 and rests against the stop 6?. If new the lever 60 is movedin the direction of the arrow, for the purpose of moving the safety bolt 3 from its operative position, a cam 68 of the lever fit] strikes the inclined surface 69 of the bolt 66 and presses the bolt to the right so that the bolt 66 is disengaged from the stop 6?. The hand lever 61 can now be moved to operate the slide.

A similar control device is shown in Figs. 12 and 13. In connection with this control device, it is assumed that the operation of the slide is started by actuating a switch H! of the pushbutton type. The hand lever 60, which,-as in the previous construction, is drawn, bya spring 62, against a stop 63 and is moved in the direction of the arrow, that is to the right, to move the safety bolt 3 from its operative position by means of a link H, is arranged so close to the push-button It! that the latter can be operated only after the hand lever 60 has been moved to the right to make the push-button I accessible. It will thus be seen that in'this construction aswell as in the construction according to Figs. and 11, premature advance run of the slide and forceful breakage of the safety device by the slide are avoided.

It may be pointed out that the invention is applicable also to such slide control devices in which "the control lever has only two positions, that is in which the advance run and the actual working stroke positions are merged in one. Moreover, the various features described 'in connection with the various constructional examples may be combined in various other ways, provided, of course, that the main features of the invention are retained. This applies, not only to the various combinations in which the safety bolt is operated either mechanically or hydraulically, but applies also to constructions in which a rotating cam shaft is used, the safety bolt being, in such cases, operated, that is, moved out of its operative position by the action of a magnet. The return movement of the safety bolt can be effected by any suitable control device, for instance, by a device which cuts the magnet out of circuit upon advance of the slide. In this case too, the safety bolt i preferably so mounted thatit can be forced backwards temporarily by the returning slide. We claim:

1.In a hydraulic press, comprising a frame, a slide mounted for reciprocating thereon, means controlling the working and return movement of said slide, an automatically projected dog mounted on said frame in position when projected for locking saidslide in returned position, an operating member for retracting said dog, and a linkage connecting said dog and operating member, the improvement herein described which consists in the said linkage including a member having lost 1 motion permitting said dog to move out of looking position, and means associated with said slide and operative upon the return movement thereof formoving said dog out of locking position.

'2. In a hydraulic press, comprising a frame, a slide mounted for reciprocating thereon, means controlling the Working and return movement'of said slide, an automatically projected dog mounted on said frame in position when projected for locking said slide in returned position, means for retracting said dog, and means limiting'the movement of said dog into locking position, the improvement herein described which consists in said dog retracting means being in the form of .a linkage including an operating member adapted to be moved into position for permitting said dog to move into locking position and to be further moved in the same direction, said linkage includ-. ing 'a member having lost motion permitting movement of said operating member whensaid dog is in looking position.

3. In a hydraulic press, comprising a frame, a'slide mounted for reciprocating thereon, means controlling the working and return movement of said slide,an automatically projected dog mounted on said frame in position when projected for locking said slide in returned position, andmeans including an operating member for retracting said dog, the improvement herein described which consists in the said operating member being operatively connected with said controlling means so that it permits the said dog to be projected into locking position when it is in the position in which said slide performs its return movement, andthe said dog retracting means being in the, form of a linkage including a member having lost motion permitting said dog to move out of locking position, and. means associated with said slide and operative upon the return movement thereof for temporarily moving, said dog out of locking position.

4. In a hydraulic press, comprising a frame, a slide mounted for reciprocating thereon, means controlling the working and return movement of saidslide, an automatically projected dog mounted on said frame in position when projected for locking said slide in returned position, and means for retracting said dog, the improvement herein described which consists, in means limiting the movement of said dog into locking positiomsaid dog retracting means being in the form of a linkage including an operating member operatively connected with said controlling means so that it is adapted to be set into position, first, for retracting said dog out of locking position, second, for permitting the dog to move into locking position and into engagement with said limiting means, and third, into position beyond said second position in the direction in which it is moved for permitting said dog to move into looking position, and said linkage including a member having lost motion permitting such movement of said operating member beyond said second position when said dog is in looking position, and means associated with said slide and operative upon the return movement thereof for temporarily moving said dog out of locking position.

5. In a hydraulic drawing press, comprising a frame, a slide mounted for reciprocating thereon, and means controlling the working and return movement of said slide, a locking dog mounted on said frame, automatic means tending to move said dog into position for locking said slide in returned position, means to limit the movement of said dog into locking position, a linkage having an operating member connected with said controlling means, said operating member having a position, first, in which said slideis in returned position and said locking dog in locking position, second, a position in which it is advanced farther in the direction in which it permits said dog to move into locking position and in which said controlling means cause return movement of said slide, and third, a position in which said controlling means cause workin movement of said slide and said locking dog is retracted out of locking position, said linkage having lost motion permitting said operating member to advance while the dog is arrested and also permitting said dog to be moved out of looking position while said operating member is in advanced position, and means associated with said slide and operative when said slide performs its return stroke to move said dog out of locking position.

6. In a hydraulic press, comprising a frame, a slide mounted for reciprocating thereon, means controlling the working and return movement of said slide, an automatically projected dog mounted on said frame in position when projected for locking said slide in returned position, and means including an operating member for retracting said dog, the improvement herein described which consist in the said operating member being operatively connected with said controlling means so that it permits the said dog to be projected into locking position when it is in the position in which said slide performs its return movement, and the said dog retracting means consisting of levers and links one composed of telescoping members and stops providing lost motion permitting said dog to move out of locking position, and means associated with said slide and operative upon the return movement thereof for temporarily moving said dog out of locking position.

7. In a. hydraulic press, comprising a frame, a slide mounted for reciprocating thereon, means controlling theworking and return movement of said slide, an automatically projected dog mounted on said frame in position when projected for locking said slide in returned position, and means for retracting said dog, the improvement herein described which consists in means limiting the movement of said dog into locking position, said dog retracting means consisting of levers, links and an operating member operatively connected with said controlling means so that it is adapted to be set thereby into position, first, for retracting said dog out of looking position, second, for permitting the dog to move into locking position and into engagement with said limiting means, and third, into position beyond said second position in the direction in which it is moved for permitting said dog to move into locking position, and one of said links being composed of telescoping members and stops providing lostmotion permitting such movement of said operating member beyond said second position when said dog is in looking position, and means associated with said slide and operative upon the return movement thereof for temporarily moving said dog out of locking position.

8. In a hydraulic drawing press, comprising a frame, a slide mounted for reciprocating thereon, and means controlling the working and return movement of said slide, a locking dog mounted-on said frame, automatic means tending to move said 'dog into position for locking said slide in returned position, means to limit the movement of said dog into locking position, an operating member connected with said controlling means, means operatively connecting said operating member with said dog and consisting of links and'levers, said operating member having a positiomfirst, in which said slide is in returned position andsaid locking dog in looking position,

second a position in which it is advanced farther in the direction in which it permits said dog to moveinto locking position and in which said controlling means cause return movement of said slide, andthird, a position inwhich said controlling means cause working movement of said slide and saidlocking dog is retracted out of looking position, one of said links consisting of telescoping members and stops providing lost motion permitting said operating member to advance while the dog is arrested and also permitting said dog to be moved out of locking position while said operating member is in advanced position, and means associated with said slide and operativewhen said slide performs its return stroke to move said dog out of locking position.

9.;In ahydraulic drawing press as claimed in claim 1, the further improvement herein described which consists in an operating member for said linkage in position for locking the said controlling means and adapted to release the same when it is operated for retracting said dog out of locking position. l

10. In a hydraulic drawing press as claimed in claim 1, the further improvement herein described which consists in hand-operated levers placed one beside the'other and operatively connected respectively with said controlling means and with'said linkage, a spring-pressed bolt mounted on said lever connected with the controlling means, a stop on said frame in position for engagement with said bolt and for preventing operation of the lever carrying the same, and a camiformed on the lever connected with said linkage and adapted to push said bolt out of locking engagement with said stop.

11. In a hydraulic press as claimed in claim 1, the further improvement described herein in which the said controlling means comprise electrical means and a push-button switch for operating the same, and in which the said linkage includes an operating member normally in position for preventing operation of said pushbutton switch and adapted to release the same when it is moved for retracting the said dog out of locking position.

ADOLPI-I HINDERER.

JAKOB STURM. 

